"There is absolutely no US policy and US support or US inclination or US military operations involved in arming paramilitaries," state department spokesman Richard Boucher said.

"Allegations that the US military personnel involved were trafficking in ammunition are, indeed, extremely troubling to us."

"As with all criminal allegations against US military personnel, we're committed to a full investigation and we'll be working with the Colombian authorities in that regard."

Delay attempt

The men are expected to be flown to the US in the next few days.

Colombian Vice President Francisco Santos said he hoped the men "will be judged and that the punishments will be similar to what they would receive here".

A senior Colombian official, Inspector General Edgardo Jose Maya, tried to have their deportation delayed, and asked for further examination of a treaty granting them immunity in Colombia.

Since 2000, the US has been funding an aid package known as Plan Colombia, under which Colombian forces receive training, equipment and intelligence to root out drug traffickers and eliminate coca crops.